Valve for the braking balancement, for a farm tractor or a similar vehicle

Abstract

A balancing valve for balancing the braking system of a vehicle equipped with two separated master cylinders for the independent braking of the wheels situated at the two sides of the vehicle, wherein at least one of two ring packings which cooperate with the intake of a transfer channel connecting both master cylinders is housed within a containment space that allows a displacement of this packing to substantially increase the volume of the space located on the packing side communicating with the transfer channel.

The invention claimed is: 
     
       1. A balancing valve (V) for a braking system of a vehicle having two separate master brake cylinders ( 1 ) configured for independent braking of respective opposite wheels of the vehicle, the two master brake cylinders connected to each other by way of a transfer channel ( 7 ), the balancing valve (V) comprising:
 a piston configured to operate within one of the master brake cylinders, the piston comprising first and second containment spaces; and 
 first and second ring packings ( 9 , 10 , 11 ) configured to cooperate with an intake ( 8 ) of the transfer channel ( 7 ), the first ring packing ( 11 ) being housed within the first containment space ( 12 , 13 ) of the piston, 
 the first containment space ( 12 , 13 ) defined in cross-section by a top surface, a side surface, and a bottom surface, 
 an expanded portion ( 13 ) of the containment space located where the top surface, side surface, and bottom surface meet, 
 the top surface having a sloped portion that slopes toward the bottom surface as a function of increasing distance from the side surface to form a narrowed portion ( 12 ) of the containment space at a location distanced from the side surface such that a displacement of the first ring packing ( 11 ) from a rest position at the expanded portion ( 13 ), resulting from an operational pressure applied through the transfer channel ( 7 ), causes the first ring packing ( 11 ) to enter the narrowed portion ( 12 ) and increases a volume of a space around the piston that is in fluid communication with an inner space of the transfer channel, 
 the first ring packing ( 11 ) configured to be contained within the expanded portion ( 13 ) under a condition of minimum elastic deformation, and the first ring packing ( 11 ) configured to penetrate into the narrowed portion ( 12 ) under a condition of increasing elastic deformation, 
 the first ring packing ( 11 ) configured to occupy the expanded portion ( 13 ) in the rest position, and configured to be displaced into the narrowed portion ( 12 ) upon application of the operational pressure, the first ring packing ( 11 ) configured to elastically deform as the first ring packing ( 11 ) displaces into the narrowed portion ( 12 ), 
 wherein the first ring packing ( 11 ) is an O-ring, and 
 wherein the second ring packing ( 9 , 10 ) is housed in the second containment space, the second ring packing comprising an O-ring ( 9 ) within the interior of the second containment space and a peripheral ring ( 10 ), configured for sealing and sliding, located at an open end of the second containment space. 
 
     
     
       2. The balancing valve (V) as set forth in  claim 1 , further comprising:
 an elastic element (M) arranged in the first containment space for operationally returning the first ring packing ( 11 ) to the rest position when the operational pressure is released. 
 
     
     
       3. The balancing valve (V) as set forth in  claim 1 , wherein an elasticity of the first ring packing ( 11 ) is sufficient to urge the first ring packing ( 11 ) from an operational position in the narrowed portion ( 12 ) into the rest position of the expanded portion ( 13 ) upon a release of the operational pressure. 
     
     
       4. The balancing valve (V) as set forth in  claim 1 , wherein the bottom wall of the containment space is formed in a cylinder wall of the one of the two master brake cylinders ( 1 ), and the top and side walls of the containment space is formed as a cavity in a surface of the piston ( 4 ).